Zinc/copper ratio: a predictor of pancreatic function in chronic pancreatitis?

The role of trace elements in the maintenance of normal pancreatic function is unclear.

To estimate trace elements (zinc and copper) in chronic pancreatitis (CP) patients and study their relationship with exocrine and endocrine insufficiency. Methods: The study involved 101 CP patients and 113 healthy controls. Disease characteristics and imaging features were recorded. Erythrocyte zinc (Zn) and copper (Cu) were estimated by flame atomic absorption spectrophotometry. Fecal pancreatic elastase1 was estimated by polyclonal antibody ELISA method as a marker of pancreatic exocrine function.

The mean erythrocyte Zn level and Zn/Cu ratio were significantly lower whereas the copper level was significantly higher in CP patients than controls. The mean Zn level and Zn/Cu ratio was significantly lower in CP patients with diabetes and those with low elastase1 as compared to non-diabetics and those with normal elastase1 respectively. Erythrocyte Cu level was significantly higher in CP patients with diabetes and with low elastase1 than those without diabetes and with normal elastase1 levels respectively. There was a significant positive correlation between elastase1 and Zn/Cu ratio (r = 0.396, p < 0.001). Receiver operating characteristic curve (ROC) analysis was performed to predict the development of exocrine insufficiency and it indicated an area under curve (AUC) of 0.838 ± 0.047 (95% CI: 0.746-0.93). The optimal cutoff value was 9.03 (sensitivity 86.5%, specificity 73.5%). When the same was performed to predict the development of diabetes, the AUC was 0.710 ± 0.05 (95% CI: 0.607-0.812). The optimal cutoff value was 7.2 (sensitivity 69.1%, specificity 69.7%).

Low erythrocyte Zn/Cu ratio was found to be associated with exocrine and endocrine insufficiency in CP patients.